Launch Vivaldi in no-ui mode

I heard that Vivaldi has no-ui mode (only webpage displayed, no tabs, no borders). This can be toggled with some key combo or saved as default setting.
But feature I am looking for is just to launch it in this mode only for this session and open some website (like Google Chrome --app). I suspect if there is such a thing it would be toggled in argv when launching from console.
Is it possible to do so?

If this depends on system, I am looking for Linux solution, but others would also be helpful

It is possible to exit Vivaldi while it is in fullscreen mode using the default Windows shortcut (Alt F4) or whatever you want to assign to it in Settings, Keyboard. If Vivaldi is set to Start with the last session, then it will launch in fullscreen mode. That is not what you asked, but perhaps it is useful for others.